Relative Imports Outside Of Src/ Are Not Supported.

7 min read Oct 11, 2024

The error "relative imports outside of src/ are not supported" is a common one encountered when working with Python projects structured using PyPI (Python Package Index) conventions. This error arises because Python's import system has specific rules for handling relative imports, especially within a package context. Let's delve deeper into the reasons behind this error and explore how to resolve it effectively.

Understanding Relative Imports

Relative imports in Python allow you to import modules or packages that reside within the same directory or subdirectories of your current module. They offer a way to organize code logically and prevent circular dependencies. Python distinguishes between two types of relative imports:

Explicit Relative Imports: These use a leading dot (.) followed by the module name (e.g., .my_module).
Implicit Relative Imports: These use a single dot (.) without a module name (e.g., from . import my_module).

The "src/" Directory Convention

The "src/" directory, commonly used in Python projects adhering to PyPI standards, serves as a designated location for source code. This directory holds the modules and packages that are meant to be part of your project. The purpose of this convention is to:

Clear Separation: Keep your project's source code distinct from other files and folders, such as tests, configuration files, or build tools.
Easier Package Management: PyPI packages are designed to be easily installed and used, and the "src/" directory simplifies this process.

Why the Error Occurs

The core reason for the error "relative imports outside of src/ are not supported" is that Python's import machinery expects your code to be organized according to the "src/" convention. When you attempt a relative import from outside the "src/" directory, Python encounters a conflict because it doesn't recognize this directory structure as the standard package layout.

Resolving the Issue: Best Practices

There are several effective ways to resolve this error. Here are some recommended approaches:

Structure Your Project Correctly:
- Utilize the "src/" Directory: Ensure that your project's source code is neatly organized within a "src/" directory. All your modules and packages should reside in this directory.
- Implement a Root "init.py" File: Add an empty "init.py" file to the root of your "src/" directory. This signals to Python that the directory is a package.
Adopt Absolute Imports:
- Directly Import Modules: Instead of relying on relative imports, utilize absolute imports. For instance, if you're in a file named "module_a.py" and need to import "module_b.py", import it as from src.module_b import ....
Consider Using Packages:
- Organize Your Code: Group related modules within packages. This helps in managing code complexity and improves readability.
Use setuptools or Poetry:
- Automating Package Building: Leverage these tools to automate the packaging process and ensure your project adheres to the "src/" directory convention.

Examples of Corrected Imports

Here are some examples showcasing the correct import approaches:

Incorrect (Relative Import Outside "src/"):

# Incorrect: This would raise the error
from . import my_module

Correct (Absolute Import):

# Correct: Absolute import using "src/"
from src.my_module import my_function

Correct (Implicit Relative Import Inside "src/"):

# Correct: Relative import inside "src/"
from . import my_module

Correct (Explicit Relative Import Inside "src/"):

# Correct: Relative import inside "src/"
from .my_module import my_function

Troubleshooting Tips

Check Your Directory Structure: Verify that your project is structured correctly with a "src/" directory containing your source code.
Inspect Import Statements: Carefully examine your import statements. Pay attention to the use of relative versus absolute imports.
Run the "setup.py" or "pyproject.toml" File: If you're using a packaging tool like setuptools or Poetry, ensure you have properly defined your package structure.
Review Your "init.py" Files: Make sure "init.py" files are present in all relevant directories and that they contain necessary import statements for packages.

Conclusion

The error "relative imports outside of src/ are not supported" is a signal that your Python project's structure needs attention. By following the best practices and employing the techniques outlined in this article, you can address this issue effectively. Remember that a well-organized project structure fosters clarity, maintainability, and scalability in your codebase.